Load Balancing on Routers and Switches PDF

LECTURE NOTE 12: LOAD BALANCING ON ROUTER What is Load Balancing?  Load balancing is the process of distributing network traffic across multiple paths or links to optimize performance, reliability, and resource utilization. Benefits:  Prevents congestion by balanci...

LECTURE NOTE 12: LOAD BALANCING ON ROUTER What is Load Balancing?  Load balancing is the process of distributing network traffic across multiple paths or links to optimize performance, reliability, and resource utilization. Benefits:  Prevents congestion by balancing traffic.  Improves network redundancy.  Enhances fault tolerance. Configuring Load Balancing on Routers 1. Static Load Balancing:  Manually configure multiple static routes to the same destination with equal costs.  Example: ip route 192.168.1.0 255.255.255.0 10.0.0.1 ip route 192.168.1.0 255.255.255.0 10.0.0.2 2. Dynamic Load Balancing:  Achieved using dynamic routing protocols like:  EIGRP: Supports unequal-cost load balancing.  OSPF and RIP: Support equal-cost load balancing. 3. Configuring Unequal-Cost Load Balancing (EIGRP):  EIGRP can distribute traffic across paths with unequal metrics using the variance command.  Steps:  Identify feasible successors.  Configure variance: router eigrp 100 variance  Adjust traffic distribution based on path reliability. 4. Verify Load Balancing:  Check routing table:  show ip route  Check traffic distribution: show ip eigrp topology Load Balancing Techniques 1. Per-Packet Load Balancing:  Distributes packets across all available paths in a round-robin manner.  Suitable for environments where latency differences between paths are negligible. Example: ip load-sharing per-packet 2. Per-Destination Load Balancing: Routes packets from the same source to the same destination along the same path.  Maintains consistent paths, avoiding out-of-order delivery. 3. Unequal-Cost Load Balancing:  Supported by EIGRP, allows traffic to be split across paths with different metrics. 4. Weighted Load Balancing:  Traffic is distributed proportionally based on path weights or bandwidth.  LECTURE NOTE 13: LOAD BALANCING ON SWITCHES What is Load Balancing on Switches?  Refers to the distribution of traffic across multiple links or interfaces in a switched network.  Enhance performance.  Provide redundancy and fault tolerance. Configuring Load Balancing on Switches 1. Link Aggregation (EtherChannel):  Combines multiple physical links into a single logical link for higher throughput and redundancy.  Configuration Steps: 1. Identify and bundle interfaces: interface range g0/1 - 2 channel-group 1 mode active 2. Configure the logical interface: interface port-channel 1 switchport mode trunk 2. Load Balancing in EtherChannel:  Load balancing is based on algorithms like: Source MAC, destination MAC. Source IP, destination IP.  Configure load balancing: port-channel load-balance src-dst-ip 3. Verify Configuration:  Check EtherChannel status: show etherchannel summary Implementing Redundancy and Failover 1. Spanning Tree Protocol (STP):  Prevents loops in a switched network.  Provides redundancy by blocking certain links until a failure occurs. 2. Rapid Spanning Tree Protocol (RSTP):  An improvement over STP with faster convergence times. 3. Hot Standby Router Protocol (HSRP):  A Cisco-proprietary protocol providing gateway redundancy. Example: interface g0/1 standby 1 ip 192.168.1.1 standby 1 priority 100 standby 1 preempt 4. Gateway Load Balancing Protocol (GLBP):  Distributes traffic across multiple gateways for load balancing and redundancy. Example: glbp 1 ip 192.168.1.1 glbp 1 load-balancing round-robin 5. Link Aggregation Control Protocol (LACP):  An open standard protocol for link aggregation.  Configured using similar steps as EtherChannel but uses LACP for negotiation